Vancouver Aquarium Presents
in conjunction with The North Pacific Universities Marine Mammal Research Consortium

Introduction:

Over about the last 30 years, Steller sea lions have declined about 80% in Alaska, where most Steller sea lions are found, and the research here at the Vancouver Aquarium is part of a huge international effort to try to figure out what might be wrong with Steller sea lion populations.

Steller Sea Lion Research Project
Panning for Gold

Andrew Trites:

This is our wet lab: it’s a place where we can do anything that is too wet, smelly, or messy to be done elsewhere. It’s a place where we are preparing fecal samples that are coming from Steller sea lion haulouts and rookeries throughout Alaska and British Columbia.

We sub-sample these for stress hormone analysis and with the remainder we bring over here to our elutriator where we can clean them up to remove the fish bones, and then determine what, in fact, Steller sea lions are eating in the wild.

This is Erin Jacob, and she is going to be putting one of our samples here into a device we call the elutriator. Essentially all the samples have been soaked in water, so they’re nice and soft, and we’ll be flushing water through here as we try to flush out anything that is water soluble so we’re left with only the hard bits. It’s a bit like panning for gold. Anything that’s heavy will stay down near the bottom, anything that’s light and unwanted will go out through the top.

What we’re interested here is in just keeping the solid bits; the bones that have come from the fish, the beaks that maybe have come from squid. Essentially any hard part that we can identify to determine what the animals once ate. And we want to reconstruct the total biomass of fish.

What we have in here are various bones that have passed through the digestive tract of the Steller sea lion. One thing that stands out are all these little beads, which are actually eye lenses. They turn out to be quite robust to digestion. And we will count all the eye lenses that are in this sample and divide it by two to determine how many fish were eaten. There’s some beaks from squid and such, we’ll go through here and identify all the different species. But the goal here is to determine number one, the species and number two, the minimum numbers of each of these species. So this will be for one sample, and as you can see we’ve got some from each site, we try to get a minimum of 70, and that way be able to say what the average sea lion was eating at this site when we went to visit it.

Scat research helps us to identify which food sources are most abundant and important to Steller sea lion populations.